Semiconductors used in optoelectronic devices — An overview

Optoelectronic applications of semiconductors have been growing rapidly. They comprise photodetectors, solar cells, light emitting diodes and lasers. This article aims to provide a general picture of the material aspect of these devices. Emphasis is placed on material selection and underlying reasons, as well as the state-of-the-art performance.     

二维半导体光电性质与器件研究进展简述

二维半导体材料,如过渡金属硫族化合物,以其在光电器件方面展现出的独特性能与巨大潜力,成为后摩尔时代有极大发展前景的新半导体材料.二维材料具有独特的光电性质,如直接带隙的电子结构,谷自旋电子学特性,强激子效应等,而利用以上性质,此类材料可用于光探测器、场效应晶体管、高效微纳传感器、光电子电路等微纳光电器件中.因此,以过渡金属硫族化合物为代表的二维半导体材料无论在基础科学与未来应用方面,都是重要的备选材料.     

掺杂铌酸锂双相位共轭镜光学谐振腔的温度特性

用带导模型和耦合波方程在强泵浦条件下建立了能反映温度特性的光折变双相位共轭镜光学谐振腔的稳态强度公式,研究了这种光腔的温度特性.相位共轭镜的温度相对于输出光功率来说存在着一个最佳值,在此温度值下输出光功率最大.不同温度下两个相位共轭镜的最佳泵浦比不同.用Ce:LiNbO3单晶和He-Ne激光构成了光折变双相位共轭镜光学谐振腔.测得的实验值与理论值基本吻合.     

Packaging investigation of optoelectronic devices

Compared with microelectronic packaging, optoelectronic packaging as a new packaging type has been developed rapidly and it will play an essential role in optical communication.In this paper, we try to summarize the development history, research status, technology issues and future prospects, and hope to provide a meaningful reference.     

Temperature dependence of latch-up characteristics in LDD CMOS devices

The incremental rate of the latch-up holding current (Ih) with decreasing temperature is larger in the bulk substrate than in the epitaxial substrate. The substrate dependence is mainly due to the difference in the temperature coefficients of the material resistivity. Although Ihincreases significantly with decreasing temperature, the latch-up triggering voltage (Vtrig) in an inverter remains relatively constant, posing a limit for VLSI device miniaturization at low temperatures.     

Temperature dependent optoelectronic properties of a non-intentionally created cleaved-coupled-cavity laser

A 1300 nm InGaAsP laser diode, degraded after the application of high voltage ESD pulses in forward direction, showed after degradation a strong longitudinal mode suppression, resulting in a single mode emission spectrum identical to the one of a cleaved-coupled-cavity laser. The room temperature threshold current after ESD induced degradation increased by about 50% and the differential quantum efficiency dropped substantially. However, even after degradation in a wide temperature range stable single mode laser operation has been achieved.     

Transient analysis of p-n-p-n optoelectronic devices

p-n-p-n optoelectronic devices were analyzed using a coupled junction model, an equivalent circuit model, and a physical model. The accuracy of these models was confirmed by comparison with experimental data. The result of the authors' analysis was a new understanding of the dynamic properties of p-n-p-n devices. The authors found that the onset of switching depends only on the voltage across the forward-biased outer junctions, not on the total applied bias. Turn-on delay is dependent on the rate of voltage change across the outer junctions and the efficiency of the laser emitter. Fast turn-off of two-terminal devices is theoretically possible by applying a reverse bias during the turn-off transient. dV/dt induced switching can be avoided by proper design. Based on the authors' models, the maximum large-signal operating frequency of two-terminal p-n-p-n devices was estimated to be ~240 MHz     

半导体光电子器件的研究进展

文章综述ＣＬＥＯ’９４及ＩＱＥＣ’９４会议报道的有关光电子器件的发展状况，叙述了大功率ＬＤ、蓝绿光ＬＤ、垂直腔面发射半导体激光器、可调谐ＬＤ及ＯＥＩＣ的最新研究进展。     

Modeling the DBR laser used as wavelength conversion device

In this paper, a novel and efficient way to model the dynamic field in optical DBR-type semiconductor devices is presented. The model accounts for the longitudinal carrier, photon, and refractive index distribution. Furthermore, the model handles both active and passive sections that may include gratings. Thus, simulations of components containing, e.g., gain sections, absorptive sections, phase sections, and gratings, placed arbitrarily along the longitudinal direction of the cavity, are possible. Here, the model has been used for studying the DBR laser as a wavelength converter. Particularly, to improve the performance of the DBT converter, the influence of system and device parameters will be discussed. Calculations show that ultrafast wavelength conversion with rise and fall times less than 50 ps can be obtained. Also, a regenerative effect simultaneous with the wavelength conversion is expected, e.g., improvements in the extinction ratio of the signal of more than 6 dB is predicted for correct design and operation of the component     

Polarization dependence of optoelectronic properties in quantumdots and quantum wires-consequences of valence-band mixing

The electronic bandstructure in quantum dots and quantum wires is studied, including the valence-band mixing effects. Based on the bandstructure, results for the polarization dependence of absorption and gain (at room temperature) are examined. The related differential gain and the α-parameter is also studied. Our results show that it is extremely important to include valence-band mixing effects in predicting the laser performance of such structures     

光神经网络中的半导体光电器件

叙述了光神经网络的基本概念，并介绍了光神经网络中使用中的半导体光电器件， 体可调制光电检测器（ＶＳＰＤ），具有内存贮光神经芯片，人工视网膜芯片，以及不对称的Ｆａｂｒｙ－Ｐｅｒｏｔ调制器（ＡＦＰＭ）的最新研究结果。     

Temperature dependence of InAs/GaAs quantum dots solar photovoltaic devices

This paper presents the temperature dependence measurements characterisation of several InAs/GaAs quantum dots （QDs） solar cell devices. The devices with cylindrical geometry were fabricated and characterised on-wafer under 20 suns in a temperature range from 300°K to 430°K. The temperature dependence parameters such as open circuit voltage, short circuit density current, fill factor and efficiency are studied in detail. The increase of temperature produces an enhancement of the short circuit current. However, the open circuit voltage is degraded because the temperature increases the recombination phenomena involved, as well as reducing the effective band gap of the semiconductor.     

Temperature dependence of gate induced drain leakage current insilicon CMOS devices

The temperature dependence of the gate induced drain leakage (GIDL) current in CMOS devices is investigated from 20K up to 300K. It is shown that, at sufficiently high electric field, the conventional band-to-band tunnelling GIDL current law is applicable down to near-liquid helium temperatures for both nand p-channel devices. The exponential factor B of the GIDL current law is found to be nearly independent of temperature. Moreover, the decrease of the GIDL current as the temperature is lowered, is shown to originate from the temperature variation of the pre-exponential coefficient A of the GIDL current law     

半导体量子电子和光电子器件分析

文章主要阐述了半导体异质结构电子的量子特性,对半导体量子电子和光电子器件进行科学的分析,其中,对电子波输运状况、库仑阻塞效应等作出了一定分析基础上,介绍了几种较为新颖的、具有代表性的量子电子器件和量子光电子器件的物理模型,并对半导体量子电子和光电子器件运行的基本原理作出了科学的理解。     

Optimum design method of optoelectronic devices using simulatedannealing

A design methodology for optimizing optoelectronic functional devices is described. The introduction of cost function for electrical and optical device characteristics enables automatic optimization by simulated annealing. The optimum design of AlGaAs/GaAs pnpn differential optical switches in consideration of light emission efficiency, light sensitivity, and switching voltage is successfully demonstrated     

Design and fabrication of integrated Si-based optoelectronic devices

We have designed and fabricated novel Si-based optoelectronic devices. To this aim, different Si-based optical sources have been made and their performances at room temperature compared. Er-doped Si p–n junctions, operating at 1.54 μm and exhibiting an efficiency of 0.05% at room temperature, have been integrated with planar Si rib waveguides using either epitaxial Si or silicon on insulators (SOI) wafers. Optical characterization of these waveguides reveals very low transmission losses (below 1 dB/cm). However, Er-doping of the waveguide core, needed for the realization of the light source, results in a large increase of the losses as a consequence of absorption by the free electrons introduced by the rare earths. These losses can be suppressed when the junction is reverse biased and the whole Er profile is embodied in the depletion layer. Since this also allows efficient pumping of Er ions by hot carriers, the performances of the diodes and of the waveguides can be suitably combined. This optimized structure has also been used to design electrically pumped optical amplifiers and lasers, whose performances have been simulated.     

Modeling of GaN optoelectronic devices and strain-inducedpiezoelectric effects

Modeling of nitride-based LEDs and laser diodes requires a fast modular tool for numerical simulation and analysis. It is required that the modeling tool reflects the primary physical processes of current injection, quantum well (QW) bound-state dynamics, QW capture, radiative, and nonradiative transitions. The model must also have the flexibility to incorporate secondary physical effects, such as induced piezoelectric strain fields due to lattice mismatch and spontaneous polarization fields. A 1-D model with a phenomenological well-capture process, similar to that developed by Tessler and Eisenstein, has been implemented. The radiative processes are calculated from first principles, and the material band structures are computed using k·p theory. The model also features the incorporation of such effects as thermionic emission at heterojunctions. Shockley-Read-Hall recombination, piezoelectric strain fields, and self-consistent calculation of the QW bound states with dynamic device operation. The set of equations underlying the model is presented, with particular emphasis on the approximations used to achieve the previously stated goals. A sample structure is analyzed, and representative physical parameters are plotted. The model is then used to analyze the effects of incorporation of the strain-induced piezoelectric fields generated by lattice mismatch and the spontaneous polarization fields. It is shown that these built-in fields can accurately account for the blue-shift phenomena observed in a number of different GaN LEDs     

面向21世纪的半导体光电子器件

面向２１ 世纪的高度信息化社会,人们正在大力开发新一代高性能半导体光电子器件,以满足高速、宽带、大容量、高清晰信息传输、存贮、处理、获取的需要。文章介绍了有关的高速ＬＤ、高速ＰＤ、大面阵ＣＣＤ、新型红外焦平面阵列、多功能集成光学器件等的发展动向。     

Temperature dependence of the optical properties of Hg1−xCdxTe

The alloy composition of Hg_1−xCd_xTe should be controlled during growth, so that the desired band gap and the lattice-matched layer may be obtained. In-situ spectroscopic ellipsometry, now commercially available, enables one to acquire spectral data during growth. If one knows the optical dielectric function as a function of alloy composition and temperature, the technique can be fully used to monitor and control temperature, the thickness, and the alloy composition. For this purpose, we first obtained temperature dependent spectral data of Hg_1−xCd_xTe by spectroscopic ellipsometry (SE). The spectral data of Hg_1−xCd_xTe with x = 1,0.235, and 0.344 were obtained from room temperature to 800Kin the photon energy range from 1.3 to 6 eV. The spectral data revealed distinctive critical point structures at E₀, E₀+Δ₀, E₁, E₁+Δ₁, E₂(X), and E₂(Σ). Critical point energies decreased and linewidths increased monotonically as temperature increased. The model for the optical dielectric function enabled (i) the critical point parameters to be determined accurately, and (ii) the spectral data to be expressed as a function of temperature within and outside the experimental range.